Methyl Chloroform continues to constrain the hydroxyl (OH) variability in the troposphere

Methyl chloroform and trichloroethylene in the environment

Food and Cosmetics Toxicology ◽

10.1016/s0015-6264(77)80399-4 ◽

1977 ◽

Vol 15 (3) ◽

pp. 239

Keyword(s):

Methyl Chloroform

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Estimates of European emissions of methyl chloroform using a Bayesian inversion method

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-9755-2014 ◽

2014 ◽

Vol 14 (18) ◽

pp. 9755-9770 ◽

Cited By ~ 17

Author(s):

M. Maione ◽

F. Graziosi ◽

J. Arduini ◽

F. Furlani ◽

U. Giostra ◽

...

Keyword(s):

Point Source ◽

High Frequency ◽

Stratospheric Ozone ◽

Montreal Protocol ◽

Source Analysis ◽

Bayesian Inversion ◽

Inversion Method ◽

Data Set ◽

Methyl Chloroform

Abstract. Methyl chloroform (MCF) is a man-made chlorinated solvent contributing to the destruction of stratospheric ozone and is controlled under the "Montreal Protocol on Substances that Deplete the Ozone Layer" and its amendments, which called for its phase-out in 1996 in developed countries and 2015 in developing countries. Long-term, high-frequency observations of MCF carried out at three European sites show a constant decline in the background mixing ratios of MCF. However, we observe persistent non-negligible mixing ratio enhancements of MCF in pollution episodes, suggesting unexpectedly high ongoing emissions in Europe. In order to identify the source regions and to give an estimate of the magnitude of such emissions, we have used a Bayesian inversion method and a point source analysis, based on high-frequency long-term observations at the three European sites. The inversion identified southeastern France (SEF) as a region with enhanced MCF emissions. This estimate was confirmed by the point source analysis. We performed this analysis using an 11-year data set, from January 2002 to December 2012. Overall, emissions estimated for the European study domain decreased nearly exponentially from 1.1 Gg yr−1 in 2002 to 0.32 Gg yr−1 in 2012, of which the estimated emissions from the SEF region accounted for 0.49 Gg yr−1 in 2002 and 0.20 Gg yr−1 in 2012. The European estimates are a significant fraction of the total semi-hemisphere (30–90° N) emissions, contributing a minimum of 9.8% in 2004 and a maximum of 33.7% in 2011, of which on average 50% are from the SEF region. On the global scale, the SEF region is thus responsible for a minimum of 2.6% (in 2003) and a maximum of 10.3% (in 2009) of the global MCF emissions.

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Review of the Literature on Methyl Chloroform

Methyl Chloroform and Trichloroethylene in the Environment ◽

10.1201/9781351074506-2 ◽

2018 ◽

pp. 5-16

Author(s):

Domingo M. Aviado ◽

Samir Zakhari ◽

Joseph A. Simaan ◽

Andrew G. Ulsamer

Keyword(s):

Review Of The Literature ◽

Methyl Chloroform

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Introduction to Methyl Chloroform

Methyl Chloroform and Trichloroethylene in the Environment ◽

10.1201/9781351074506-1 ◽

2018 ◽

pp. 3-3

Author(s):

Domingo M. Aviado ◽

Samir Zakhari ◽

Joseph A. Simaan ◽

Andrew G. Ulsamer

Keyword(s):

Methyl Chloroform

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Laboratory study on heterogeneous decomposition of methyl chloroform on various standard aluminosilica clay minerals as a potential tropospheric sink

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-3-1843-2003 ◽

2003 ◽

Vol 3 (2) ◽

pp. 1843-1891

Author(s):

S. Kutsuna ◽

L. Chen ◽

O. Ohno ◽

N. Negishi ◽

K. Takeuchi ◽

...

Keyword(s):

Relative Humidity ◽

Clay Minerals ◽

Reaction Rate ◽

Ground Surface ◽

Reaction Rate Constant ◽

Pseudo First Order Reaction ◽

Dry Air ◽

Reaction Rate Constants ◽

Methyl Chloroform ◽

Bet Equation

Abstract. Methyl chloroform (1,1,1-trichloroethane, CH3CCl3) was found to decompose heterogeneously on seven types of standard clay minerals (23 materials) in dry air at 313 K in the laboratory. All reactions proceeded through the elimination of HCl; CH3CCl3 was converted quantitatively to CH2=CCl2. The activities of the clay minerals were compared via their pseudo-first-order reaction rate constants (k1). A positive correlation was observed between the k1 value and the specific surface area (S) of clay minerals, where the S value was determined by means of the general Brunauer-Emmett-Teller (BET) equation. The k1 value was anti-correlated with the value of n, a parameter of the general BET equation, and correlated with the water content that can be removed easily from the clay minerals. The reaction required no special pretreatment of clay minerals, such as heating at high temperatures; hence, the reaction can be expected to occur in the environment. Photoillumination by wavelengths present in the troposphere did not accelerate the decomposition of CH3CCl3, but it induced heterogeneous photodecomposition of CH2=CCl2. The temperature dependence of k1, the adsorption constants of CH3CC3 and CH2=CCl2, and a surface reaction rate constant were determined for an illite sample. The k1 value increased with increasing temperature. The amount of CH3CCl3 adsorbed on the illite during the reaction was proportional to the partial pressure of CH3CCl3. The reaction was sensitive to relative humidity and the k1 value decreased with increasing relative humidity. However, the reaction was found to proceed at a relative humidity of 22% at 313 K, although the k1 value was about one-twentieth of the value in dry air. The conditions required for the reaction may be present in major desert regions of the world. A simple estimation indicates that the possible heterogeneous decomposition of CH3CC3 on the ground surface in arid regions is worth taking into consideration when inferring the tropospheric lifetime of CH3CC3 and global OH concentration from the global budget concentration of CH3CCl3.

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Multi-species inversion of CH<sub>4</sub>, CO and H<sub>2</sub> emissions from surface measurements

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-5281-2009 ◽

2009 ◽

Vol 9 (14) ◽

pp. 5281-5297 ◽

Cited By ~ 83

Author(s):

I. Pison ◽

P. Bousquet ◽

F. Chevallier ◽

S. Szopa ◽

D. Hauglustaine

Keyword(s):

Transport Model ◽

Regional Scale ◽

Surface Concentration ◽

Temporal Variations ◽

Global Scale ◽

Chemical Transport Model ◽

Methyl Chloroform ◽

Emission Fluxes ◽

Surface Measurements ◽

One Year

Abstract. In order to study the spatial and temporal variations of the emissions of greenhouse gases and of their precursors, we developed a data assimilation system and applied it to infer emissions of CH4, CO and H2 for one year. It is based on an atmospheric chemical transport model and on a simplified scheme for the oxidation chain of hydrocarbons, including methane, formaldehyde, carbon monoxide and molecular hydrogen together with methyl chloroform. The methodology is exposed and a first attempt at evaluating the inverted fluxes is made. Inversions of the emission fluxes of CO, CH4 and H2 and concentrations of HCHO and OH were performed for the year 2004, using surface concentration measurements of CO, CH4, H2 and CH3CCl3 as constraints. Independent data from ship and aircraft measurements and satellite retrievals are used to evaluate the results. The total emitted mass of CO is 30% higher after the inversion, due to increased fluxes by up to 35% in the Northern Hemisphere. The spatial distribution of emissions of CH4 is modified by a decrease of fluxes in boreal areas up to 60%. The comparison between mono- and multi-species inversions shows that the results are close at a global scale but may significantly differ at a regional scale because of the interactions between the various tracers during the inversion.

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